IMPACT OF CLIMATE CHANGE
AGRICULTURE AND FOOD SECURITY
Climate change significantly affects both crop yield and the types of crops that can be cultivated in different regions. It influences key agricultural inputs such as irrigation water availability, solar radiation for plant growth, and the prevalence of pests. A notable consequence of climate change is the rise in temperature due to elevated greenhouse gas emissions. These warming impacts agriculture differently across latitudes. For instance, moderate warming (an increase of 1 to 3°C) may improve crop productivity in temperate regions. However, in tropical and subtropical regions, even a 1 to 2°C increase could lead to adverse impacts on the yield of major cereal crops. A rise beyond 3°C is likely to harm crop production in nearly all regions.
- The Sixth Assessment Report of the IPCC (2023) highlighted that developing countries, particularly the poorest nations, would face the worst consequences of climate change, including a sharp decline in agricultural output. According to the report, crop yields in tropical and sub-tropical zones are expected to fall due to reduced water availability and the emergence of new pests and insects. In South Asia, important staple crops like rice, millet, and maize may witness losses ranging from 10% to 100% by 2030.
- Climate change also influences arable land availability. In high-latitude areas, the melting of snow is expected to increase the amount of cultivable land. On the contrary, coastal arable land is likely to shrink due to rising sea levels. Additionally, problems such as coastal erosion, shoreline submergence, and salinity increase from rising sea levels will adversely affect low-lying agricultural zones.
- A study by the International Commission for Snow and Ice (ICSE) revealed that Himalayan glaciers, which act as the primary dry-season water sources for major Asian rivers like the Ganges, Indus, Brahmaputra, Yangtze, Mekong, Salween, and Yellow, are shrinking faster than glaciers in other parts of the world. If this trend continues, these glaciers may completely disappear by 2035.
- In low-income developing nations of Asia and Africa, reduced agricultural productivity due to climate change could severely threaten rural livelihoods and significantly increase food insecurity.
Impacts on Indian Agriculture
A significant portion of India’s arable land is rain-fed, meaning that the productivity of Indian agriculture is deeply dependent on the amount and pattern of rainfall. Therefore, any variation in rainfall — whether an overall increase or decrease — can adversely impact agriculture. More importantly, it is not just the total rainfall but the timing and distribution that is critical. Irregular rainfall patterns pose a severe threat to agricultural output, thereby affecting the economy and food security of the country.
- Currently, summer monsoon rainfall contributes nearly 70% of India’s total annual rainfall, making it crucial for crop cultivation. However, climate projections suggest a decline in summer monsoon rainfall by the 2050s. Additionally, semi-arid regions in western India are expected to receive more rainfall than usual due to rising temperatures, whereas central India could face a 10–20% decline in winter rainfall by the same period.
- Even minor climatic changes can lead to major disruptions in water availability, particularly in arid and semi-arid regions like northwestern India. This can severely constrain water supply for irrigation.
The productivity of most crops is projected to decline, particularly due to a rise in temperature and reduced water availability, especially in critical farming regions such as the Indo-Gangetic plains. Additionally, rabi (winter) crops are expected to suffer more than kharif (monsoon) crops.
- As temperatures rise, crops will require more fertilizers to maintain the same level of productivity, leading to increased greenhouse gas (GHG) emissions, higher ammonia volatilization, and an overall rise in cultivation costs.
- Furthermore, the frequency of extreme weather events such as droughts, floods, storms, and cyclones is expected to increase, making agricultural production more erratic and unstable.
Water Stress and Water Insecurity
The lack of access to safe and adequate water is a growing concern, especially in developing countries, where water scarcity directly affects health, sanitation, and livelihoods. With climate change, the stress on already strained water resources is expected to intensify significantly. Projections indicate that by 2025, an estimated 2 to 3 billion people will be subjected to increased water stress due to the effects of global warming.
- This widespread water scarcity is not only undermining food security but also igniting competition for water, both within nations and across borders. As the global population continues to grow and the demand for water rises, challenges related to water availability are set to worsen in the coming decades.
- Rising temperatures around the globe, largely driven by climate change, have led to the melting of mountain glaciers and a reduction in snow cover in both hemispheres. This decline is expected to accelerate throughout the 21st century, drastically affecting the availability of freshwater, reducing hydropower generation, and disrupting the seasonal flow of rivers that depend on meltwater from major mountain ranges like the Hindu-Kush, Himalayas, and Andes.
- By the 2050s, freshwater availability is expected to decline in key regions including Central, South, East, and Southeast Asia, particularly across large river basins. A warmer climate will intensify the hydrologic cycle, bringing about changes in rainfall patterns, and significantly altering the volume and timing of river runoff.
- Current research suggests a likely increase in the frequency and intensity of heavy rainfall events in many areas. In contrast, some regions may experience a decline in average rainfall, leading to an overall reduction in water resources. Already, the incidence of severe floods in major river basins has increased during the 20th century, posing a challenge to infrastructure, public safety, and water quality.
- Rising temperatures also impact the physical, chemical, and biological properties of freshwater bodies like lakes and rivers, often with negative effects on aquatic species, ecosystem diversity, and overall water quality. Furthermore, sea-level rise in coastal regions is worsening groundwater salinisation, which further restricts access to potable water, intensifying water resource constraints in vulnerable areas.
Rise in Sea Levels
- The rise in global sea levels is primarily driven by two key factors: the thermal expansion of seawater as it warms and the melting of ice sheets and glaciers. Since the early 1990s, satellite observations have confirmed that the rate of sea level rise since 1993 has been significantly higher than the average recorded over the previous 50 years. According to the IPCC, the pace of sea-level rise may accelerate dramatically if ice sheet disintegration intensifies. With global temperatures increasing by 3 to 4°C, it is estimated that around 330 million people could be permanently or temporarily displaced due to flooding. Additionally, warmer oceans are likely to generate more intense tropical storms, further exacerbating the threat.
Impacts on Coastal States in India
- India’s coastal regions face considerable risks due to rising sea levels. States like Maharashtra, Goa, and Gujarat are especially vulnerable, where coastal flooding could damage not just the infrastructure but also agricultural lands and residential areas. Among them, Goa is expected to be the worst affected, potentially losing a substantial portion of its land area, including its iconic beaches and tourism infrastructure.
- In Mumbai, the northern suburbs, such as Versova beach and other areas located along tidal mudflats and creeks, are particularly at risk of inundation and land loss. Such flooding events are expected to displace large populations, adding pressure on urban infrastructure and worsening the challenges of rapid urbanisation.
- Another critical consequence of sea-level rise is the percolation of seawater into freshwater sources, leading to scarcity of potable water. The eastern coast, especially Odisha, is likely to face more intense cyclones, placing both ecosystems and human settlements at risk.
- Furthermore, India’s rich marine biodiversity is also under threat. Coral reefs located in biosphere reserves are highly sensitive to salinity changes, and rising sea levels endanger not only these reefs but also the phytoplankton, fish stocks, and coastal communities dependent on them. People living in the Ganges Delta are among the most vulnerable, as flood risks in this low-lying region continue to rise with the advancing sea.
Impacts of Climate Change on India’s Biodiversity
- India, known for its mega biodiversity, spans diverse ecosystems—from the Himalayan glaciers to the Thar Desert. However, climate change is increasingly threatening the balance and resilience of these ecosystems.
Mountain Ecosystems and the Himalayas
- India’s mountain ecosystems are biodiversity hotspots. However, rising temperatures and unsustainable human activities are causing habitat fragmentation and ecological degradation. The Himalayan region, which hosts the largest concentration of glaciers outside the polar regions, plays a pivotal role in sustaining perennial rivers such as the Ganga, Yamuna, and Brahmaputra. These rivers are lifelines not only for India but also for neighboring countries like Nepal, Bhutan, China, and Pakistan.
- The retreat of Himalayan glaciers poses severe risks. The Glacial Lake Outburst Floods (GLOFs) are projected to become more frequent in the Eastern and Central Himalayas, causing devastating floods downstream, endangering lives, farmlands, forests, and infrastructure. As glaciers melt, it directly affects agricultural productivity, especially in the Indo-Gangetic plains, where over 65–70% of Indians are dependent on agriculture.
Desert Ecosystems
- India’s desert ecosystems, particularly the arid and semi-arid zones, occupy 38.8% of the country’s land area and extend across 10 states. These regions are home to diverse desert fauna, including many migratory bird species. However, climate-induced desertification is expanding these zones. Events such as the 2006 floods in Barmer district (Rajasthan) illustrate the increasing unpredictability in these regions, where climate change has altered the natural arid attributes.
Coastal and Marine Ecosystems
- India’s coastal and marine ecosystems, especially mangrove forests, are critical for biodiversity. These wetlands act both as carbon sinks and as natural barriers against cyclones and sea-level rise. However, climate change has led to alarming instances of coral bleaching, which reflects the vulnerability of marine ecosystems.
Peninsular Ecosystem and Monsoon Dependency
- The rivers of Peninsular India are largely monsoon-fed, making the entire Peninsular ecosystem highly monsoon-dependent. Any variation in monsoon patterns significantly affects agriculture, water supply, and biodiversity. India’s climatic stability, essential for sustaining its biodiversity, is increasingly at risk due to shifting rainfall patterns.
Climate Change and Human Health
General Health Impacts
Climate change is emerging as a global public health crisis, endangering human survival across the world. Every year:
- About 3.9 million deaths are caused by air pollution.
- 1.8 million die from diarrhoeal diseases linked to poor sanitation and hygiene.
- Around 3.5 million deaths result from malnutrition.
- Nearly 50,000 lives are lost to natural disasters.
Rising temperatures exacerbate air pollution, water contamination, and foodborne illnesses. Extreme weather events, such as heatwaves, floods, and droughts, have a direct impact on human health.
Water and Sanitation-Related Diseases
- Floods and droughts disrupt freshwater supplies. During droughts, water scarcity impairs hygiene, while floods contaminate water sources, leading to increased outbreaks of diarrhoeal diseases. Asia, particularly East, South, and Southeast Asia, is expected to see rising mortality from such water-related diseases due to hydrological imbalances.
- Floods also create favorable breeding grounds for vectors like mosquitoes, increasing the prevalence of diseases like malaria and Japanese encephalitis. In disaster-affected areas, mass migration and overcrowding lead to poor sanitary conditions, amplifying disease transmission.
Spread of Vector-Borne Diseases
As temperatures rise, disease-carrying insects spread to new geographical areas. Malaria, once restricted to lower altitudes, has been reported in countries like Nepal and Bhutan due to warming. WHO estimates suggest that 200 to 300 million more people could be at risk of malaria, a disease that already causes around 619,000 deaths annually. Similarly, dengue fever has reached higher altitudes in Latin America and East Asia. It is projected that:
- 90 million more people in Africa could be exposed to malaria by 2030.
- 2 billion more people worldwide could face dengue risk by the 2080s.
Food Security and Nutrition
- Rising temperatures and changing precipitation are projected to reduce crop yields in many developing countries. This threatens food security and leads to widespread malnutrition, especially in Africa, where rain-fed agriculture yields could drop by up to 50% by 2020.
Ozone Depletion and Health Risks
- Emissions of greenhouse gases have contributed to the depletion of the ozone layer, which acts as a protective shield against harmful ultraviolet (UV) radiation. Increased exposure to UV rays can lead to a rise in skin cancer, eye diseases such as cataracts, and even immune suppression.
Disproportionate Impact on the Poor
- Both WHO and IPCC studies highlight that climate change impacts on health will disproportionately affect the poor and vulnerable populations, who already suffer from inadequate health care and limited resilience. This worsens inequality between the affluent and the underprivileged.
Regional Variation in Health Impacts
- The health consequences of climate change will not be uniform. Different regions will experience varying levels of risk, and these will continue to change over time as global temperatures rise further.